Scientists have found the chemical calcium percholate which would suck
moisture out of the air and keep water liquid on the surface

Mars may hold liquid water raising the chances of finding life on the Red Planet.

Although scientists have long known that there is frozen water at the poles of Mars, new research suggests that salty liquid water could be present close to the planet’s surface.

Liquid water has not itself been found, but Nasa’s Mars rover Curiosity has found calcium percholate – a type of salt – in the soil.

Like throwing salt onto ice to melt it, calcium percholate lowers the temperature at which water freezes and would allow it to exist in liquid form even on the frozen surface of Mars. The temperature on the surface of Mars varies between -195 F (-125 C) in winter to 70F (20C) in summer.

Calcium Percholate also absorbs water that is present in the atmosphere, dragging it down into the surface.

All life on Earth requires water to live, so the prospect of liquid water on the planet’s surface raises the chance that some kind of primitive alien life-form could be discovered. Recently life has been discovered on Earth which can live entirely in brine without needing oxygen. The creatures, Loriciferans, are only a millimetre long and resemble jellyfish encased in shells.

“Liquid water is a requirement for life as we know it, and a target for Mars exploration missions,” said the report’s lead author, Javier Martin-Torres of the Spanish Research Council, Spain, and Lulea University of Technology, Sweden, and a member of Curiosity’s science team.

“Conditions near the surface of present-day Mars are hardly favorable for microbial life as we know it, but the possibility for liquid brines on Mars has wider implications for habitability and geological water-related processes.”

The Curiosity Rover has been probing the Gale crater, just south of the equator, since it landed in 2012.

Nasa's Curiosity Rover has been on Mars since 2012

The geography of the area suggests the whole of Gale crater may have once been a large lake, as Curiosity has found clear sedimentary deposits. There are also rounded pebbles which show that at some point flowing water with a depth of around one metre was present on the planet.

Around 4.5 billion years ago, Mars had 6.5 times as much water as it does now and a thicker atmosphere. But most of this water has disappeared out into space because Mars lost its magnetic field which protected the planet from cosmic radiation from the Sun. Without that protection Mars lost most of its atmosphere which is now around 100 times thinner than Earth’s.

Last December the Curiosity Rover discovered spikes of methane which could be the first hint of biological life living on Mars.

Water is sucked into salts on the surface of Mars where it can stay liquid. Source: University of Copenhagan

Most methane on Earth is produced as a waste gas by living organisms and it is possible that the ‘burps’ of the gas may have been produced by bacteria.

The question of whether there is, or was, life on Mars may finally be answered by the European Space Agency's ExoMars mission, which will land a 300kg rover on the Red Planet in 2019.

Experts Mars will be equipped with a two-metre drill and the ability to detect biomarkers of life. It will not be heading for Gale Crater, however. Because it will land with less precision than Curiosity, the crater and its mountain are considered too potentially hazardous.

“We have discovered the substance calcium perchlorate in the soil and, under the right conditions, it absorbs water vapour from the atmosphere,” said Dr Morten Madsen, associate professor and head of the Mars Group at the Niels Bohr Institute at the University of Copenhagen.

“Our measurements from the Curiosity rover’s weather monitoring station show that these conditions exist at night and just after sunrise in the winter.

“Based on measurements of humidity and the temperature at a height of 1.6 meters and at the surface of the planet, we can estimate the amount of water that is absorbed.

“When night falls, some of the water vapor in the atmosphere condenses on the planet surface as frost, but calcium perchlorate is very absorbent and it forms a brine with the water, so the freezing point is lowered and the frost can turn into a liquid.”

This ball-like pebble on the surface of Mars proves that a river once flowed through the area